A digital Purim noisemaker: Slap the evil Haman and watch his eyes bounce.
Purim goes digital: This toy app emulates a gragger (ra'ashan). Shake it or slap evil Haman and watch his eyes bounce. Fun for kids, but watch your phone!
Note: If you don't know what a gragger is, maybe you shouldn't download it. It does exactly what a gragger is supposed to do. No more, no less.